Despite the publicity about the paperless office, paper remains an important media in today's working environment. Many efforts have been made to integrate paper documents with computer-based information systems. These efforts generally involve two scenarios. The first scenario involves scanning an existing physical document to create a digital copy, assigning a digital file name and then managing the digital copy as any other digital file. The second scenario involves creation of a physical document from an exiting digital document or file such as by printing. To aid in the integration process, a barcode or a Dataglyph may be printed or otherwise attached to a physical document. Dataglyphs are generally less visually disruptive than barcodes. Both barcodes and Dataglyphs provide a means for the computer to grasp intentionally printed information on the paper document. Since both are generally applied at the time the information is recorded on the sheet of paper (but may be applied later through the use of an adhesive label), both generally appear on the same face of the sheet of paper as the recorded information.
The use of edge marking of sheet materials has been proposed for various applications. U.S. Pat. No. 5,085,417, issued Feb. 4, 1992, to Copham, for “Method of Encoding Stacks of Printed Material”, describes a process for using edge markings to identify one customer's order for form checks from another customer's. During manufacture of a sheet of checks, a coded image is provided at the cutting boundaries of the stock sheets, so that when the checks are cut from the stock, an identification code appears on the checks when viewed from the edge. An edge-visible code is obtained by cutting the paper precisely where marks are located. A different code is provided for each customer to enable workers to look at the stacked check books at the edge to determine if another customer's checks were erroneously placed. Each check in a stack of checks for a particular customer has the same edge code as all other checks for that customer; the edge code is not unique from check to check.
U.S. Pat. No. 6,585,163, issued Jul. 1, 2003, to Meunier et al., for “Encoded Sheet Material and System for Processing” (the '163 patent), describes an encoded sheet material in which the edge of the material has indicia arranged thereon to form a code uniquely identifying the sheet of material. The '163 patent also describes a system for processing these codes and various methods for marking the edge of each sheet of paper at paper production time, in order to uniquely identify each ream and each sheet in the ream.
U.S. Pat. No. 6,499,665, issued Dec. 31, 2002, to Meunier et al., for “Method for Indexing and Retrieval of Physical Documents”, describes a method and system for managing and retrieving a physical document having a unique edge code.
One method described in the '163 patent marks the edge of each sheet of paper (stacked in a ream) at paper production time, in order to uniquely identify each ream and each sheet in the ream. The proposed coding scheme combines a barcode for identifying the ream and a so-called ‘offset-line’ for identifying each sheet in the ream. This marking method enables an entire ream of paper to be marked at once. However, codes created using this method are sometimes difficult to read with precision (due to the location of the offset measure). It was also sometimes difficult to mark more than one edge on the ream at the same time using this method; vertically aligning the slope lines on all four edges (in order to apply the same code on all edges) can be difficult.
U.S. Pat. No. 6,637,666, issued Oct. 28, 2003, to Meunier, for “Coding Scheme for Encoded Sheet Material”, describes how a Vernier-based pattern can improve on the readability of the offset measure used in the '163 patent. U.S. Pat. No. 6,637,666 describes an edge coding scheme for an encoded sheet material including an offset mark located at an offset distance from a reference mark on the edge of the sheet of material and a plurality of equally spaced clock marks disposed along the edge, such that the offset distance can be approximated by the product of the number of clock marks between the reference mark and the offset mark times the distance between successive clock marks. Another edge coding scheme includes coincidence between a first plurality of equally spaced apart clock marks and a second plurality of equally spaced Vernier marks, where the second plurality is less than the first plurality.
U.S. Pat. No. 6,582,138, issued Jun. 24, 2003, to Meunier et al., for “Authenticated Sheet Material”, and U.S. Pat. No. 6,604,875, issued Aug. 12, 2003, to Meunier et al., for “Authenticated Sheet Material”, describe a method of creating an authenticable sheet of material including marking an edge of the sheet of material with a unique code, measuring a physical property of the materials, recording the measured physical property of the sheet of material in a database indexed by the edge code. To verify the validity of a sheet of material, the edge code is read, the physical property is measured and the measured value compared with the stored value in the database associated with the edge code. If the two values are substantially equal, the sheet of material is authentic.
U.S. Pat. No. 6,335,084, issued Jan. 1, 2002, to Biegelsen et al., for “Encoded Sheet Material and Sheet Processing Apparatus Using Encoded Sheet Material”, describes pre-marking of edges of paper reams/stacks (during manufacture) with information related to the paper's physical properties (e.g., its weight, color). This encoded information is read and used by printers (and other recording devices which record information on the faces of the sheet material) when selecting paper from paper trays.
It would be desirable to have a method which would permit easier creation of unique codes on up to four edges of a sheet of material. It would be desirable to have a method which would permit code creation at paper production time.